Role of counterion condensation in folding of the Tetrahymena ribozyme.: I.: Equilibrium stabilization by cations
Role of counterion condensation in folding of the Tetrahymena ribozyme.: I.: Equilibrium stabilization by cations
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DOI：
10.1006/jmbi.2001.4437
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发表时间：
2001-03-09
影响因子：
5.6
通讯作者：
Woodson, SA
中科院分区：
文献类型：
--
作者：
Heilman-Miller, SL;Thirumalai, D;Woodson, SA
RNA折叠成有序的紧凑结构需要带正电荷的抗衡离子对带负电荷的主链进行实质性中和。利用天然凝胶电泳分析，我们已经研究了四膜虫核酶的平衡折叠后的平衡缩合的影响。在一价、二价和三价离子的存在下孵育核酶诱导能够在短暂暴露于Mg 2+时快速形成天然结构的构象状态。这种过渡的阳离子浓度依赖性与用于诱导折叠的抗衡离子的电荷直接相关。底物裂解测定证实了在这些条件下催化活性的快速开始。这些结果进行了讨论的经典反离子凝聚理论。提出了一个折叠模型，该模型预测了电荷、离子半径和温度对反离子诱导的RNA折叠转变的影响。(C)北京：科学出版社.
Folding of RNA into an ordered, compact structure requires substantial neutralization of the negatively charged backbone by positively charged counterions. Using a native gel electrophoresis assay, we have examined the effects of counterion condensation upon the equilibrium folding of the Tetrahymena ribozyme. Incubation of the ribozyme in the presence of mono-, di- and trivalent ions induces a conformational state that is capable of rapidly forming the native structure upon brief exposure to Mg2+. The cation concentration dependence of this transition is directly correlated with the charge of the counterion used to induce folding. Substrate cleavage assays confirm the rapid onset of catalytic activity under these conditions. These results are discussed in terms of classical counter-ion condensation theory. A model for folding is proposed which predicts effects of charge, ionic radius and temperature on counterion-induced RNA folding transitions. (C) 2001 Academic Press.